Method of treating plants or plant tissues with C-16,17-dihydro gibberellins

Abstract

A method is provided for treating plants or plant tissues (including cuttings, roots, bulbs, corns, tubers, rhizomes and seeds) in order to induce a desired tissue morphology and/or a desired physiological state by applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to produce an at least partial inhibition of the formation of effector gibberellins in said plant. Effects obtainable include dwarfing, stem and shoot and/or root (radicle) growth retardation, flowering, improved fruit quality, inhibiting fruit ripening, improving fruit set, controlling weed growth, inducing male sterility, retarded bud break and tillering.

We claim: 
     
       1. A method for promoting a desired tissue morphology and/or physiological state in a higher plant, wherein said desired tissue morphology or physiological state is selected from at least one of (i) dwarfing   (ii) stem and shoot and/or root (radicle) growth retardation   (iii) flowering   (iv) improved fruit quality   (v) inhibiting fruit ripening   (vi) improving fruit set   (vii) controlling weed growth   (viii) inducing male sterility   (ix) retarded bud break   (x) tillering which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to promote the desired tissue morphology and/or physiological state in the plant.     
     
     
       2. A method for promoting a desired tissue morphology and/or physiological state in a higher plant, wherein said desired tissue morphology or physiological state is selected from at least one of (i) dwarfing   (ii) stem and shoot and/or root (radicle) growth retardation   (iii) flowering   (iv) improved fruit quality   (v) inhibiting fruit ripening   (vi) improving fruit set   (vii) controlling weed growth   (viii) inducing male sterility   (ix) retarded bud break   (x) tillering which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to produce an at least partial inhibition of gibberellin 3β-hydroxylase activity in said plant.     
     
     
       3. A method for promoting a desired tissue morphology and/or physiological state in a higher plant wherein said desired tissue morphology or physiological state is selected from at least one of (i) dwarfing   (ii) stem and shoot and/or root (radicle) growth retardation   (iii) flowering   (iv) improved fruit quality   (v) inhibiting fruit ripening   (vi) improving fruit set   (vii) controlling weed growth   (viii) inducing male sterility   (ix) retarded bud break   (x) tillering which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or a C-16,17-dihydro gibberellin precursor effective to produce at least partial inhibition of the formation of effector gibberellins in said plant.     
     
     
       4. A method for promoting flowering in a higher plant, which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to promote flowering. 
     
     
       5. A method according to claim 4 wherein flowering is promoted (a) with a simultaneous retardation of stem or shoot elongation or (b) with a nil or negligible effect on stem or shoot elongation. 
     
     
       6. A method for retarding stem or shoot growth in a higher plant, which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to promote flowering. 
     
     
       7. A method for improving fruit quality in a higher plant, which comprises applying to the plant an effective amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       8. A method for inhibiting ripening of fruit of a higher plant plant, which comprises applying to the plant an effective amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       9. A method for improving fruit set in a higher plant, which comprises applying to the plant an effective amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       10. A method of controlling growth of weeds in an area of land which comprises applying to said land area a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       11. A method for inducing male sterility in a higher plant, which comprises applying to the plant an effective amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       12. A method for retarding bud break in a higher plant, which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to promote flowering. 
     
     
       13. A method for inhibiting formation of effector gibberellins in a plant, which comprises applying to the plant an amount of a C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor. 
     
     
       14. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor has a formula selected from formulae Ia, Ib, Ic, Id and Ie: ##STR4## wherein A,B,C,D, E and F independently represent hydrogen atoms or hydroxyl groups and the dotted line represents one optional double bond either between the carbon atoms in positions 1 and 2 or between the carbon atoms in positions 2 and 3. 
     
     
       15. A method according to claim 1 wherein the gibberellin precursor is selected from C-16,17-dihydro steviol, C-16,17-dihydro ent-kaurene, C-16,17-dihydro ent-kaurenoic acid, C-16,17-dihydro-7-hydroxy kaurenoic acids, C-16,17-dihydro-16,17-dihydroxy kaurenoic acids and C-16,17-dihydro kaurenoic acids. 
     
     
       16. A method according to claim 1 wherein the gibberellin or gibberellin precursor is the C-2,3 dehydro, or C-1,2 dehydro derivative of a C-16,17-dihydro gibberellin or a C-16,17-dihydro gibberellin precursor. 
     
     
       17. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor has a hydroxy substituent in the 17-position. 
     
     
       18. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor has a hydroxy substituent in both the 16- and the 17-positions. 
     
     
       19. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor has the hydroxylation pattern and stereochemical structure of GA5. 
     
     
       20. A method according to claim 14 wherein said C-16,17-dihydro gibberellin is selected from C-16,17-dihydro gibberellin A 3  and C-16,17-dihydro gibberellin A 5 . 
     
     
       21. A method according to claim 1 wherein said gibberellin is selected from: C-16.17-dihydro GA 3  ;   C-16,17-dihydro GA 20  ;   C-16,17-dihydro,2,3 didehydro GA 9  ;   C-16,17-dihydro,1,2 didehydro GA 9  ;   C-16,17-dihydro GA 12  ;   C-16,17-dihydro GA 15  ;   C-16,17-dihydro GA 53  ;   the C-2,3dehydro derivative of C-16,17-dihydro GA 12  ;   the C-2,3dehydro derivative of C-16,17-dihydro GA 15  ;   the C-2,3dehydro derivative of C-16,17-dihydro GA 53  ;   the C-1,2-dehydro derivative of C-16,17-dihydro GA 20  ;   the C-1,2-dehydro derivative of C-16,17-dihydro GA 12  ;   the C-1,2-dehydro derivative of C-16,17-dihydro GA 15  ; and   the C-1,2-dehydro derivative of C-16,17-dihydro GA 53 .   
     
     
       22. A method according to claim 20 wherein said gibberellin is C-16,17-dihydro GA 5 . 
     
     
       23. A method according to claim 1 wherein said C-16,17-dihydro gibberellin or gibberellin precursor is applied in the form of a free acid or salts or esters thereof. 
     
     
       24. A method according to claim 23 wherein said salts and esters are selected from sodium and potassium salts and the C 1-4  carboxylic acid esters. 
     
     
       25. A method according to claim 1 wherein said C-16,17-dihydro gibberellin or gibberellin precursor is applied together with another plant growth regulators. 
     
     
       26. A method according to claim 1 wherein said C-16,17-dihydro gibberellin or gibberellin precursor is applied by spraying a solution or suspension thereof to whole plants, or by seed application, together with a suitable carrier. 
     
     
       27. A method according to claim 1 wherein said C-16,17-dihydro gibberellin or gibberellin precursor is applied at a rate of from 2 to 100 micrograms per gram fresh weight of actively growing plant tissue. 
     
     
       28. A method according to claim 1 wherein said C-16,17-dihydro gibberellin or gibberellin precursor is applied at a concentrations of from 2-600 ppm, preferably from 5-450 ppm. 
     
     
       29. A method according to claim 1 wherein the plant species is a floriculturally, agronomically, or horticulturally useful monocot or dicot, or gymnosperm, including woody ornamental or fruiting shrubs, or woody ornamental or fruiting trees, or a conifer of the Gymnospermae Order. 
     
     
       30. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor is applied prior to natural floral initiation. 
     
     
       31. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor is applied after natural floral initiation, but during early stages of floral differentiation. 
     
     
       32. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor is applied during early stages of floral development. 
     
     
       33. A method according to claim 1 wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor is applied to dry, imbibed or imbibing seeds so as to ovecome a natural requirement for low temperature, particularly to obviate vernalization). 
     
     
       34. A method according to claim 1 wherein the plant species is a member of the Gramineae. 
     
     
       35. A method according to claim 34 wherein the plant species is wheat or barley. 
     
     
       36. A method according to claim 1 wherein the plant species is oilseed rape. 
     
     
       37. A method according to claim 1 wherein the plant species is a member of the Araceae. 
     
     
       38. A method according to claim 1 wherein the plant species is any monocotyledenous or dicotyledenous plant with a natural requirement for cold to promote flowering. 
     
     
       39. A method according to claim 1 wherein the gibberellin is applied as a seed soak in an appropriate aqueous or organic solution yielding an uptake by the seed of from 1 picogram to 10 micrograms per seed. 
     
     
       40. A method according to claim 1 wherein the gibberellin is applied at a rate of 10 nanograms to 100 milligrams per plant for herbaceous plants (the effective dose depending on species and size of plant), 10 micrograms to 500 milligrams per plant for shrubs, and at a rate of 1 milligram to 20 grams per plant for trees. 
     
     
       41. A method according to claim 1 wherein the gibberellin is at a concentration up to 5000 ppm. 
     
     
       42. A method according to claim 1 wherein the gibberellin is at a concentration of from 1 to 3000 ppm. 
     
     
       43. A method according to claim 1 wherein the gibberellin is at a concentration in the range from 1-1000 ppm. 
     
     
       44. A method according to claim 1 wherein the gibberellin is applied at a concentration in the range from 5-1000 ppm as a foliar spray and/or as a soil drench. 
     
     
       45. A method according to claim 1 wherein the gibberellin is applied at a concentration in the range from 5-350 ppm as a foliar spray and/or as a soil drench. 
     
     
       46. A method according to claim 1 wherein the gibberellin is applied as a seed soak at a concentration in the range of 10 -12  to 1.5×10 -2  molar. 
     
     
       47. A method according to claim 1 wherein the gibberellin is applied as a seed soak at a concentration in the range of 10 -12  to 10 -7  molar. 
     
     
       48. A method according to claim 1 wherein the gibberellin is applied at a rate of up to 1000 micrograms/gram fresh weight. 
     
     
       49. A method according to claim 1 wherein the gibberellin is applied at a rate of from 1 to 1000 micrograms/gram fresh weight. 
     
     
       50. A method according to claim 1 wherein the gibberellin is applied at a rate of from 2 to 1000 micrograms/gram fresh weight. 
     
     
       51. A method according to claim 1 wherein the gibberellin is applied at a rate of from 2 to 500 micrograms/gram fresh weight. 
     
     
       52. A method according to claim 1 wherein the gibberellin is applied at a rate of from 2 to 333 micrograms/gram fresh weight. 
     
     
       53. A method according to claim 1 wherein the gibberellin is applied at a rate of from 2 to 100 micrograms/gram fresh weight. 
     
     
       54. A composition comprising an amount of C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor effective to promote, in a higher plant, a desired tissue morphology and/or physiological state selected from at least one of (i) dwarfing   (ii) stem and shoot and/or root (radicle) growth retardation   (iii) flowering   (iv) improved fruit quality   (v) inhibiting fruit ripening   (vi) improving fruit set   (vii) controlling weed growth   (viii) inducing male sterility   (ix) retarded bud break   (x) tillering, together with an agriculturally or horticulturally acceptable diluent or carrier.     
     
     
       55. A composition according to claim 54, wherein said composition is substantially free of gibberellins which are C-16,17-dehydro. 
     
     
       56. A composition according to claim 54, wherein the C-16,17-dihydro gibberellin or C-16,17-dihydro gibberellin precursor is as defined in any one of claims 14 to 24. 
     
     
       57. A composition according to claim 54, wherein said gibberellin or gibberellin precursor is contained in a concentration of up to 5,000 ppm. 
     
     
       58. A composition according to claim 54, wherein said gibberellin or gibberellin precursor is contained in a concentration of from 1 to 3,000 ppm. 
     
     
       59. A composition according to claim 54, wherein said gibberellin or gibberellin precursor contained in a concentration of from 1 to 1,000 ppm.